Polynya signature simulation method polynya area in comparison to AMSR-E 89 GHz sea-ice concentrations in the Ross Sea and off the Adeflie Coast, Antarctica, for 2002-05: first results

The Polynya Signature Simulation Method (PSSM) is applied to Special Sensor Microwave/ Imager observations from different Defense Meteorological Satellite Program spacecraft for 2002-05 to analyze the polynya area in the Ross Sea (Ross Ice Shelf polynya (RISP) and Terra Nova Bay polynya (TNBP)) and off the Adelie Coast (Mertz Glacier polynya (MGP)), Antarctica, on a sub-daily scale. The RISP and the MGP exhibit similar average total polynya areas. Major area changes (> 10000km(2); TNPB: > 2000km(2)) occur over a range of 2-3 to 20days in all regions. Sub-daily area changes are largest for the MGP (5800km(2)) and smallest for the TNBP (800km(2)), underlining the persistence of the forcing of the latter. ARTIST sea-ice (ASI) algorithm concentration maps obtained using 89GHz Advanced Microwave Scanning Radiometer (AMSR-E) data are compared to PSSM maps, yielding convincing agreement in the average, similarly detailed winter polynya distribution. Average ASI algorithm ice concentrations take values of 25-40% and 65-80% for the PSSM open-water and thin-ice class, respectively. The discrepancy with expected values (0% and 100%) can be explained by the different spatial resolution and frequency used by the methods. A new land mask and a mask to flag icebergs are introduced. Comparison of PSSM maps with thermal ice thickness based on AVHRR infrared temperature and ECMWF ERA-40 data suggests an upper thickness limit for the PSSM thin-ice class of 20-25 cm.